rename - change the name or location of a file
int rename(const char *oldpath, const char *newpath);
rename renames a file, moving it between directories if required.
Any other hard links to the file (as created using link(2)) are unaffected.
If newpath already exists it will be atomically replaced (subject to a few conditions - see ERRORS below), so that there is no point at which another process
attempting to access newpath will find it missing.
If newpath exists but the operation fails for some reason rename guarantees to leave an instance of newpath in place.
However, when overwriting there will probably be a window in which both oldpath and newpath refer to the file being renamed.
If oldpath refers to a symbolic link the link is renamed; if newpath refers to a symbolic link the link will be overwritten.
On success, zero is returned. On error, -1 is returned, and errno is set appropriately.
- newpath is an existing directory, but oldpath is not a directory.
- oldpath and newpath are not on the same filesystem.
- ENOTEMPTY or EEXIST
- newpath is a non-empty directory, i.e., contains entries other than '.' and '..'.
- The rename fails because oldpath or newpath is a directory that is in use by some process (perhaps as current working directory, or as root directory, or because it was open for reading) or is in use by the system (for example as mount point), while the system considers this an error. (Note that there is no requirement to return EBUSY in such cases - there is nothing wrong with doing the rename anyway - but it is allowed to return EBUSY if the system cannot otherwise handle such situations.)
- The new pathname contained a path prefix of the old, or, more generally, an attempt was made to make a directory a subdirectory of itself.
- oldpath already has the maximum number of links to it, or it was a directory and the directory containing newpath has the maximum number of links.
- A component used as a directory in oldpath or newpath is not, in fact, a directory. Or, oldpath is a directory, and newpath exists but is not a directory.
- oldpath or newpath points outside your accessible address space.
- Write access to the directory containing oldpath or newpath is not allowed for the process's effective uid, or one of the directories in oldpath or
newpath did not allow search (execute) permission, or oldpath was a directory and did not allow write permission (needed to update the .. entry).
- EPERM or EACCES
- The directory containing oldpath has the sticky bit set and the process's effective uid is neither that of root nor the uid of the file to be deleted nor that of the directory containing it, or newpath is an existing file and the directory containing it has the sticky bit set and the process's effective uid is neither that of root nor the uid of the file to be replaced nor that of the directory containing it, or the filesystem containing pathname does not support renaming of the type requested.
- oldpath or newpath was too long.
- A directory component in oldpath or newpath does not exist or is a dangling symbolic link.
- Insufficient kernel memory was available.
- The file is on a read-only filesystem.
- Too many symbolic links were encountered in resolving oldpath or newpath.
- The device containing the file has no room for the new directory entry.
POSIX, 4.3BSD, ANSI C
On NFS filesystems, you can not assume that if the operation failed the file was not renamed. If the server does the rename operation and then crashes, the retransmitted RPC which will be processed when the server is up again causes a failure. The application is expected to deal with this. See link(2) for a similar problem.
link(2), unlink(2), symlink(2), mv(1)